Close to the sacristy door, but raised to a considerable height above the choir floor, stands a round column (see Fig. 983), which supports two pointed arches. These arches appear to have opened into an upper aisle or chapel. They are carved with rows of dog-tooth or nail-head ornaments, which have the appearance of thirteenth century work; but as they are [Illustration: FIG. 984.--Iona Cathedral. View from South-East.] much decayed, they are probably of the late date to which, as we have seen, many examples of imitation dog-tooth enrichments at Iona and elsewhere belong. The parapet of the choir (see Fig. 984) is simple, and is supported on massive corbels, like those common in the castles of Scotland. The water of the gutters escapes by small apertures through the parapet. [Illustration: FIG. 985.--Iona Cathedral. Choir Pier and Arch of South Aisle.] The nave contains a good western doorway of late design (Fig. 994), with three orders of mouldings in the jambs, which have no caps, but have the jamb mouldings carried round the pointed arch. The nave and transepts have no aisles. The windows of the nave (Fig. 995) are much damaged. At each end of the south wall is a small single pointed light, [Illustration: FIG. 986.--Iona Cathedral. Sedilia and Piscina in Choir.] and there has been a triple light window, with tracery, in the centre. The single light window at the east end of the nave has a carved head, with a water table over it, inserted above the window. Part of the north [Illustration: FIG. 987.--Iona Cathedral. Door to Sacristy.] wall of the nave is demolished (see Fig. 994), and a door to the cloister near the west end has been built up (see Plan). The north transept has two deeply-arched recesses in the east wall, containing small windows and a central arched recess, which seems to have contained a statue. This is apparently the oldest part of the whole edifice, the arches, shafts, and caps in the east wall (Fig. 996) having very much the character of transition work. A small window in the west wall, raised so as to be above the cloister roof (see Fig. 994), throws light on the point where the altar stood. [Illustration: FIG. 988.--Iona Cathedral. Caps of Doorway to Sacristy.] The south transept is 22 feet by 17 feet, and is lighted by a three light traceried window in the south gable wall (see Fig. 984), and a small window placed at a considerable height in the west wall (see Fig. 995). The parapet and corbel table are the same as those of the choir. The crossing has four arches opening into the choir, nave, and transepts, which carry a tower, 29 feet by 25 feet, over the walls, rising to two stories in height above the eaves, and crowned with a plain parapet, supported on simple corbels (see Figs. 984 and 994). The upper story has rectangular windows on each face, three of them filled with tracery of late patterns, and the one on the north with a window containing simple tracery